Key Terms 4 & 5 Flashcards
(24 cards)
Nucleus
In physical science, an atoms central region, which is made up of protons and nuetrons
Electron
A subatomic particle that has a negative charge
Proton
A subatomic particle that has a positive charge and that is located in the nucleus of an atom; the number of protons in the nucleus is the atomic number, which determines the identity of an element
Neutron
A subatomic particle that has no change and that is located in the nucleus of an atom
Atomic number
The number of protons in the nucleus of an atom; the atomic number is the same for all atoms of an element
Mass number
The sum of all the numbers of protons and nuetrons
Isotope
An atom that has the same number of protons as other atoms of the same element do but that has a different number of neutrons
Unified atomic mass unit
A unit of mass that describes the mass of an atom or molecule
Mole
The SI base unit used to measure the amount of a substance whose number of particles is the same as the number of atoms of carbon is exactly 12 g of carbon-12
Orbital
A region in an atom where there is a high probability of finding electrons
Valence electrons
An electron that is found in the outermost shell of an atom that determines the atom’s chemical properties
Photon
A unit or quantum of light; a particle of electromagnetic radiation that has zero rest mass and carries a quantum of energy
Periodic law
The law that states that the repeating chemical and physical properties of elements change periodically with the atomic numbers of the elements
Period
In chemistry, a horizontal row of elements in the periodic table
Group
A vertical column of elements in the periodic table; elements in q group share chemical properties
Ion
An atom, radical, or molecule that has gained or lost one or more electrons and has a negative or positive charge
Metal
An element that is shiny and that conducts heat and electricity well
Nonmetal
An element that conducts heat and electricity poorly and that does not form positive ions in an electrolytic solution
Semiconductor
An element or compound that conducts electric current better than an insulator does but not as well as a conductor
Alkali metal
One of the elements of the Group 1 of the periodic table (not hydrogen)
Alkaline-earth metal
One of the elements of Group 2 of the periodic table
Transition metal
One of the metals that can use the inner shell before the outer shell to bond
Noble gas
One of the elements of Group 18 of the periodic table; unreactive
Halogen
One of the elements of Group 17 of the periodic table; combine with metals to form salts
